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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* auditfilter.c -- filtering of audit events
3 *
4 * Copyright 2003-2004 Red Hat, Inc.
5 * Copyright 2005 Hewlett-Packard Development Company, L.P.
6 * Copyright 2005 IBM Corporation
7 */
8
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/kernel.h>
12 #include <linux/audit.h>
13 #include <linux/kthread.h>
14 #include <linux/mutex.h>
15 #include <linux/fs.h>
16 #include <linux/namei.h>
17 #include <linux/netlink.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/security.h>
21 #include <net/net_namespace.h>
22 #include <net/sock.h>
23 #include "audit.h"
24
25 /*
26 * Locking model:
27 *
28 * audit_filter_mutex:
29 * Synchronizes writes and blocking reads of audit's filterlist
30 * data. Rcu is used to traverse the filterlist and access
31 * contents of structs audit_entry, audit_watch and opaque
32 * LSM rules during filtering. If modified, these structures
33 * must be copied and replace their counterparts in the filterlist.
34 * An audit_parent struct is not accessed during filtering, so may
35 * be written directly provided audit_filter_mutex is held.
36 */
37
38 /* Audit filter lists, defined in <linux/audit.h> */
39 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
40 LIST_HEAD_INIT(audit_filter_list[0]),
41 LIST_HEAD_INIT(audit_filter_list[1]),
42 LIST_HEAD_INIT(audit_filter_list[2]),
43 LIST_HEAD_INIT(audit_filter_list[3]),
44 LIST_HEAD_INIT(audit_filter_list[4]),
45 LIST_HEAD_INIT(audit_filter_list[5]),
46 LIST_HEAD_INIT(audit_filter_list[6]),
47 #if AUDIT_NR_FILTERS != 7
48 #error Fix audit_filter_list initialiser
49 #endif
50 };
51 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
52 LIST_HEAD_INIT(audit_rules_list[0]),
53 LIST_HEAD_INIT(audit_rules_list[1]),
54 LIST_HEAD_INIT(audit_rules_list[2]),
55 LIST_HEAD_INIT(audit_rules_list[3]),
56 LIST_HEAD_INIT(audit_rules_list[4]),
57 LIST_HEAD_INIT(audit_rules_list[5]),
58 LIST_HEAD_INIT(audit_rules_list[6]),
59 };
60
61 DEFINE_MUTEX(audit_filter_mutex);
62
63 static void audit_free_lsm_field(struct audit_field *f)
64 {
65 switch (f->type) {
66 case AUDIT_SUBJ_USER:
67 case AUDIT_SUBJ_ROLE:
68 case AUDIT_SUBJ_TYPE:
69 case AUDIT_SUBJ_SEN:
70 case AUDIT_SUBJ_CLR:
71 case AUDIT_OBJ_USER:
72 case AUDIT_OBJ_ROLE:
73 case AUDIT_OBJ_TYPE:
74 case AUDIT_OBJ_LEV_LOW:
75 case AUDIT_OBJ_LEV_HIGH:
76 kfree(f->lsm_str);
77 security_audit_rule_free(f->lsm_rule);
78 }
79 }
80
81 static inline void audit_free_rule(struct audit_entry *e)
82 {
83 int i;
84 struct audit_krule *erule = &e->rule;
85
86 /* some rules don't have associated watches */
87 if (erule->watch)
88 audit_put_watch(erule->watch);
89 if (erule->fields)
90 for (i = 0; i < erule->field_count; i++)
91 audit_free_lsm_field(&erule->fields[i]);
92 kfree(erule->fields);
93 kfree(erule->filterkey);
94 kfree(e);
95 }
96
97 void audit_free_rule_rcu(struct rcu_head *head)
98 {
99 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
100 audit_free_rule(e);
101 }
102
103 /* Initialize an audit filterlist entry. */
104 static inline struct audit_entry *audit_init_entry(u32 field_count)
105 {
106 struct audit_entry *entry;
107 struct audit_field *fields;
108
109 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
110 if (unlikely(!entry))
111 return NULL;
112
113 fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
114 if (unlikely(!fields)) {
115 kfree(entry);
116 return NULL;
117 }
118 entry->rule.fields = fields;
119
120 return entry;
121 }
122
123 /* Unpack a filter field's string representation from user-space
124 * buffer. */
125 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
126 {
127 char *str;
128
129 if (!*bufp || (len == 0) || (len > *remain))
130 return ERR_PTR(-EINVAL);
131
132 /* Of the currently implemented string fields, PATH_MAX
133 * defines the longest valid length.
134 */
135 if (len > PATH_MAX)
136 return ERR_PTR(-ENAMETOOLONG);
137
138 str = kmalloc(len + 1, GFP_KERNEL);
139 if (unlikely(!str))
140 return ERR_PTR(-ENOMEM);
141
142 memcpy(str, *bufp, len);
143 str[len] = 0;
144 *bufp += len;
145 *remain -= len;
146
147 return str;
148 }
149
150 /* Translate an inode field to kernel representation. */
151 static inline int audit_to_inode(struct audit_krule *krule,
152 struct audit_field *f)
153 {
154 if (krule->listnr != AUDIT_FILTER_EXIT ||
155 krule->inode_f || krule->watch || krule->tree ||
156 (f->op != Audit_equal && f->op != Audit_not_equal))
157 return -EINVAL;
158
159 krule->inode_f = f;
160 return 0;
161 }
162
163 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
164
165 int __init audit_register_class(int class, unsigned *list)
166 {
167 __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
168 if (!p)
169 return -ENOMEM;
170 while (*list != ~0U) {
171 unsigned n = *list++;
172 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
173 kfree(p);
174 return -EINVAL;
175 }
176 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
177 }
178 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
179 kfree(p);
180 return -EINVAL;
181 }
182 classes[class] = p;
183 return 0;
184 }
185
186 int audit_match_class(int class, unsigned syscall)
187 {
188 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
189 return 0;
190 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
191 return 0;
192 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
193 }
194
195 #ifdef CONFIG_AUDITSYSCALL
196 static inline int audit_match_class_bits(int class, u32 *mask)
197 {
198 int i;
199
200 if (classes[class]) {
201 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
202 if (mask[i] & classes[class][i])
203 return 0;
204 }
205 return 1;
206 }
207
208 static int audit_match_signal(struct audit_entry *entry)
209 {
210 struct audit_field *arch = entry->rule.arch_f;
211
212 if (!arch) {
213 /* When arch is unspecified, we must check both masks on biarch
214 * as syscall number alone is ambiguous. */
215 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
216 entry->rule.mask) &&
217 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
218 entry->rule.mask));
219 }
220
221 switch(audit_classify_arch(arch->val)) {
222 case 0: /* native */
223 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
224 entry->rule.mask));
225 case 1: /* 32bit on biarch */
226 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
227 entry->rule.mask));
228 default:
229 return 1;
230 }
231 }
232 #endif
233
234 /* Common user-space to kernel rule translation. */
235 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
236 {
237 unsigned listnr;
238 struct audit_entry *entry;
239 int i, err;
240
241 err = -EINVAL;
242 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
243 switch(listnr) {
244 default:
245 goto exit_err;
246 #ifdef CONFIG_AUDITSYSCALL
247 case AUDIT_FILTER_ENTRY:
248 pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
249 goto exit_err;
250 case AUDIT_FILTER_EXIT:
251 case AUDIT_FILTER_TASK:
252 #endif
253 case AUDIT_FILTER_USER:
254 case AUDIT_FILTER_EXCLUDE:
255 case AUDIT_FILTER_FS:
256 ;
257 }
258 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
259 pr_err("AUDIT_POSSIBLE is deprecated\n");
260 goto exit_err;
261 }
262 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
263 goto exit_err;
264 if (rule->field_count > AUDIT_MAX_FIELDS)
265 goto exit_err;
266
267 err = -ENOMEM;
268 entry = audit_init_entry(rule->field_count);
269 if (!entry)
270 goto exit_err;
271
272 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
273 entry->rule.listnr = listnr;
274 entry->rule.action = rule->action;
275 entry->rule.field_count = rule->field_count;
276
277 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
278 entry->rule.mask[i] = rule->mask[i];
279
280 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
281 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
282 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
283 __u32 *class;
284
285 if (!(*p & AUDIT_BIT(bit)))
286 continue;
287 *p &= ~AUDIT_BIT(bit);
288 class = classes[i];
289 if (class) {
290 int j;
291 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
292 entry->rule.mask[j] |= class[j];
293 }
294 }
295
296 return entry;
297
298 exit_err:
299 return ERR_PTR(err);
300 }
301
302 static u32 audit_ops[] =
303 {
304 [Audit_equal] = AUDIT_EQUAL,
305 [Audit_not_equal] = AUDIT_NOT_EQUAL,
306 [Audit_bitmask] = AUDIT_BIT_MASK,
307 [Audit_bittest] = AUDIT_BIT_TEST,
308 [Audit_lt] = AUDIT_LESS_THAN,
309 [Audit_gt] = AUDIT_GREATER_THAN,
310 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
311 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
312 };
313
314 static u32 audit_to_op(u32 op)
315 {
316 u32 n;
317 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
318 ;
319 return n;
320 }
321
322 /* check if an audit field is valid */
323 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
324 {
325 switch(f->type) {
326 case AUDIT_MSGTYPE:
327 if (entry->rule.listnr != AUDIT_FILTER_EXCLUDE &&
328 entry->rule.listnr != AUDIT_FILTER_USER)
329 return -EINVAL;
330 break;
331 case AUDIT_FSTYPE:
332 if (entry->rule.listnr != AUDIT_FILTER_FS)
333 return -EINVAL;
334 break;
335 }
336
337 switch(entry->rule.listnr) {
338 case AUDIT_FILTER_FS:
339 switch(f->type) {
340 case AUDIT_FSTYPE:
341 case AUDIT_FILTERKEY:
342 break;
343 default:
344 return -EINVAL;
345 }
346 }
347
348 switch(f->type) {
349 default:
350 return -EINVAL;
351 case AUDIT_UID:
352 case AUDIT_EUID:
353 case AUDIT_SUID:
354 case AUDIT_FSUID:
355 case AUDIT_LOGINUID:
356 case AUDIT_OBJ_UID:
357 case AUDIT_GID:
358 case AUDIT_EGID:
359 case AUDIT_SGID:
360 case AUDIT_FSGID:
361 case AUDIT_OBJ_GID:
362 case AUDIT_PID:
363 case AUDIT_PERS:
364 case AUDIT_MSGTYPE:
365 case AUDIT_PPID:
366 case AUDIT_DEVMAJOR:
367 case AUDIT_DEVMINOR:
368 case AUDIT_EXIT:
369 case AUDIT_SUCCESS:
370 case AUDIT_INODE:
371 case AUDIT_SESSIONID:
372 /* bit ops are only useful on syscall args */
373 if (f->op == Audit_bitmask || f->op == Audit_bittest)
374 return -EINVAL;
375 break;
376 case AUDIT_ARG0:
377 case AUDIT_ARG1:
378 case AUDIT_ARG2:
379 case AUDIT_ARG3:
380 case AUDIT_SUBJ_USER:
381 case AUDIT_SUBJ_ROLE:
382 case AUDIT_SUBJ_TYPE:
383 case AUDIT_SUBJ_SEN:
384 case AUDIT_SUBJ_CLR:
385 case AUDIT_OBJ_USER:
386 case AUDIT_OBJ_ROLE:
387 case AUDIT_OBJ_TYPE:
388 case AUDIT_OBJ_LEV_LOW:
389 case AUDIT_OBJ_LEV_HIGH:
390 case AUDIT_WATCH:
391 case AUDIT_DIR:
392 case AUDIT_FILTERKEY:
393 break;
394 case AUDIT_LOGINUID_SET:
395 if ((f->val != 0) && (f->val != 1))
396 return -EINVAL;
397 /* FALL THROUGH */
398 case AUDIT_ARCH:
399 case AUDIT_FSTYPE:
400 if (f->op != Audit_not_equal && f->op != Audit_equal)
401 return -EINVAL;
402 break;
403 case AUDIT_PERM:
404 if (f->val & ~15)
405 return -EINVAL;
406 break;
407 case AUDIT_FILETYPE:
408 if (f->val & ~S_IFMT)
409 return -EINVAL;
410 break;
411 case AUDIT_FIELD_COMPARE:
412 if (f->val > AUDIT_MAX_FIELD_COMPARE)
413 return -EINVAL;
414 break;
415 case AUDIT_EXE:
416 if (f->op != Audit_not_equal && f->op != Audit_equal)
417 return -EINVAL;
418 break;
419 }
420 return 0;
421 }
422
423 /* Translate struct audit_rule_data to kernel's rule representation. */
424 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
425 size_t datasz)
426 {
427 int err = 0;
428 struct audit_entry *entry;
429 void *bufp;
430 size_t remain = datasz - sizeof(struct audit_rule_data);
431 int i;
432 char *str;
433 struct audit_fsnotify_mark *audit_mark;
434
435 entry = audit_to_entry_common(data);
436 if (IS_ERR(entry))
437 goto exit_nofree;
438
439 bufp = data->buf;
440 for (i = 0; i < data->field_count; i++) {
441 struct audit_field *f = &entry->rule.fields[i];
442
443 err = -EINVAL;
444
445 f->op = audit_to_op(data->fieldflags[i]);
446 if (f->op == Audit_bad)
447 goto exit_free;
448
449 f->type = data->fields[i];
450 f->val = data->values[i];
451
452 /* Support legacy tests for a valid loginuid */
453 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
454 f->type = AUDIT_LOGINUID_SET;
455 f->val = 0;
456 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
457 }
458
459 err = audit_field_valid(entry, f);
460 if (err)
461 goto exit_free;
462
463 err = -EINVAL;
464 switch (f->type) {
465 case AUDIT_LOGINUID:
466 case AUDIT_UID:
467 case AUDIT_EUID:
468 case AUDIT_SUID:
469 case AUDIT_FSUID:
470 case AUDIT_OBJ_UID:
471 f->uid = make_kuid(current_user_ns(), f->val);
472 if (!uid_valid(f->uid))
473 goto exit_free;
474 break;
475 case AUDIT_GID:
476 case AUDIT_EGID:
477 case AUDIT_SGID:
478 case AUDIT_FSGID:
479 case AUDIT_OBJ_GID:
480 f->gid = make_kgid(current_user_ns(), f->val);
481 if (!gid_valid(f->gid))
482 goto exit_free;
483 break;
484 case AUDIT_ARCH:
485 entry->rule.arch_f = f;
486 break;
487 case AUDIT_SUBJ_USER:
488 case AUDIT_SUBJ_ROLE:
489 case AUDIT_SUBJ_TYPE:
490 case AUDIT_SUBJ_SEN:
491 case AUDIT_SUBJ_CLR:
492 case AUDIT_OBJ_USER:
493 case AUDIT_OBJ_ROLE:
494 case AUDIT_OBJ_TYPE:
495 case AUDIT_OBJ_LEV_LOW:
496 case AUDIT_OBJ_LEV_HIGH:
497 str = audit_unpack_string(&bufp, &remain, f->val);
498 if (IS_ERR(str))
499 goto exit_free;
500 entry->rule.buflen += f->val;
501
502 err = security_audit_rule_init(f->type, f->op, str,
503 (void **)&f->lsm_rule);
504 /* Keep currently invalid fields around in case they
505 * become valid after a policy reload. */
506 if (err == -EINVAL) {
507 pr_warn("audit rule for LSM \'%s\' is invalid\n",
508 str);
509 err = 0;
510 }
511 if (err) {
512 kfree(str);
513 goto exit_free;
514 } else
515 f->lsm_str = str;
516 break;
517 case AUDIT_WATCH:
518 str = audit_unpack_string(&bufp, &remain, f->val);
519 if (IS_ERR(str))
520 goto exit_free;
521 entry->rule.buflen += f->val;
522
523 err = audit_to_watch(&entry->rule, str, f->val, f->op);
524 if (err) {
525 kfree(str);
526 goto exit_free;
527 }
528 break;
529 case AUDIT_DIR:
530 str = audit_unpack_string(&bufp, &remain, f->val);
531 if (IS_ERR(str))
532 goto exit_free;
533 entry->rule.buflen += f->val;
534
535 err = audit_make_tree(&entry->rule, str, f->op);
536 kfree(str);
537 if (err)
538 goto exit_free;
539 break;
540 case AUDIT_INODE:
541 err = audit_to_inode(&entry->rule, f);
542 if (err)
543 goto exit_free;
544 break;
545 case AUDIT_FILTERKEY:
546 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
547 goto exit_free;
548 str = audit_unpack_string(&bufp, &remain, f->val);
549 if (IS_ERR(str))
550 goto exit_free;
551 entry->rule.buflen += f->val;
552 entry->rule.filterkey = str;
553 break;
554 case AUDIT_EXE:
555 if (entry->rule.exe || f->val > PATH_MAX)
556 goto exit_free;
557 str = audit_unpack_string(&bufp, &remain, f->val);
558 if (IS_ERR(str)) {
559 err = PTR_ERR(str);
560 goto exit_free;
561 }
562 entry->rule.buflen += f->val;
563
564 audit_mark = audit_alloc_mark(&entry->rule, str, f->val);
565 if (IS_ERR(audit_mark)) {
566 kfree(str);
567 err = PTR_ERR(audit_mark);
568 goto exit_free;
569 }
570 entry->rule.exe = audit_mark;
571 break;
572 }
573 }
574
575 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
576 entry->rule.inode_f = NULL;
577
578 exit_nofree:
579 return entry;
580
581 exit_free:
582 if (entry->rule.tree)
583 audit_put_tree(entry->rule.tree); /* that's the temporary one */
584 if (entry->rule.exe)
585 audit_remove_mark(entry->rule.exe); /* that's the template one */
586 audit_free_rule(entry);
587 return ERR_PTR(err);
588 }
589
590 /* Pack a filter field's string representation into data block. */
591 static inline size_t audit_pack_string(void **bufp, const char *str)
592 {
593 size_t len = strlen(str);
594
595 memcpy(*bufp, str, len);
596 *bufp += len;
597
598 return len;
599 }
600
601 /* Translate kernel rule representation to struct audit_rule_data. */
602 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
603 {
604 struct audit_rule_data *data;
605 void *bufp;
606 int i;
607
608 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
609 if (unlikely(!data))
610 return NULL;
611 memset(data, 0, sizeof(*data));
612
613 data->flags = krule->flags | krule->listnr;
614 data->action = krule->action;
615 data->field_count = krule->field_count;
616 bufp = data->buf;
617 for (i = 0; i < data->field_count; i++) {
618 struct audit_field *f = &krule->fields[i];
619
620 data->fields[i] = f->type;
621 data->fieldflags[i] = audit_ops[f->op];
622 switch(f->type) {
623 case AUDIT_SUBJ_USER:
624 case AUDIT_SUBJ_ROLE:
625 case AUDIT_SUBJ_TYPE:
626 case AUDIT_SUBJ_SEN:
627 case AUDIT_SUBJ_CLR:
628 case AUDIT_OBJ_USER:
629 case AUDIT_OBJ_ROLE:
630 case AUDIT_OBJ_TYPE:
631 case AUDIT_OBJ_LEV_LOW:
632 case AUDIT_OBJ_LEV_HIGH:
633 data->buflen += data->values[i] =
634 audit_pack_string(&bufp, f->lsm_str);
635 break;
636 case AUDIT_WATCH:
637 data->buflen += data->values[i] =
638 audit_pack_string(&bufp,
639 audit_watch_path(krule->watch));
640 break;
641 case AUDIT_DIR:
642 data->buflen += data->values[i] =
643 audit_pack_string(&bufp,
644 audit_tree_path(krule->tree));
645 break;
646 case AUDIT_FILTERKEY:
647 data->buflen += data->values[i] =
648 audit_pack_string(&bufp, krule->filterkey);
649 break;
650 case AUDIT_EXE:
651 data->buflen += data->values[i] =
652 audit_pack_string(&bufp, audit_mark_path(krule->exe));
653 break;
654 case AUDIT_LOGINUID_SET:
655 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
656 data->fields[i] = AUDIT_LOGINUID;
657 data->values[i] = AUDIT_UID_UNSET;
658 break;
659 }
660 /* fall through - if set */
661 default:
662 data->values[i] = f->val;
663 }
664 }
665 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
666
667 return data;
668 }
669
670 /* Compare two rules in kernel format. Considered success if rules
671 * don't match. */
672 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
673 {
674 int i;
675
676 if (a->flags != b->flags ||
677 a->pflags != b->pflags ||
678 a->listnr != b->listnr ||
679 a->action != b->action ||
680 a->field_count != b->field_count)
681 return 1;
682
683 for (i = 0; i < a->field_count; i++) {
684 if (a->fields[i].type != b->fields[i].type ||
685 a->fields[i].op != b->fields[i].op)
686 return 1;
687
688 switch(a->fields[i].type) {
689 case AUDIT_SUBJ_USER:
690 case AUDIT_SUBJ_ROLE:
691 case AUDIT_SUBJ_TYPE:
692 case AUDIT_SUBJ_SEN:
693 case AUDIT_SUBJ_CLR:
694 case AUDIT_OBJ_USER:
695 case AUDIT_OBJ_ROLE:
696 case AUDIT_OBJ_TYPE:
697 case AUDIT_OBJ_LEV_LOW:
698 case AUDIT_OBJ_LEV_HIGH:
699 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
700 return 1;
701 break;
702 case AUDIT_WATCH:
703 if (strcmp(audit_watch_path(a->watch),
704 audit_watch_path(b->watch)))
705 return 1;
706 break;
707 case AUDIT_DIR:
708 if (strcmp(audit_tree_path(a->tree),
709 audit_tree_path(b->tree)))
710 return 1;
711 break;
712 case AUDIT_FILTERKEY:
713 /* both filterkeys exist based on above type compare */
714 if (strcmp(a->filterkey, b->filterkey))
715 return 1;
716 break;
717 case AUDIT_EXE:
718 /* both paths exist based on above type compare */
719 if (strcmp(audit_mark_path(a->exe),
720 audit_mark_path(b->exe)))
721 return 1;
722 break;
723 case AUDIT_UID:
724 case AUDIT_EUID:
725 case AUDIT_SUID:
726 case AUDIT_FSUID:
727 case AUDIT_LOGINUID:
728 case AUDIT_OBJ_UID:
729 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
730 return 1;
731 break;
732 case AUDIT_GID:
733 case AUDIT_EGID:
734 case AUDIT_SGID:
735 case AUDIT_FSGID:
736 case AUDIT_OBJ_GID:
737 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
738 return 1;
739 break;
740 default:
741 if (a->fields[i].val != b->fields[i].val)
742 return 1;
743 }
744 }
745
746 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
747 if (a->mask[i] != b->mask[i])
748 return 1;
749
750 return 0;
751 }
752
753 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
754 * re-initialized. */
755 static inline int audit_dupe_lsm_field(struct audit_field *df,
756 struct audit_field *sf)
757 {
758 int ret = 0;
759 char *lsm_str;
760
761 /* our own copy of lsm_str */
762 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
763 if (unlikely(!lsm_str))
764 return -ENOMEM;
765 df->lsm_str = lsm_str;
766
767 /* our own (refreshed) copy of lsm_rule */
768 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
769 (void **)&df->lsm_rule);
770 /* Keep currently invalid fields around in case they
771 * become valid after a policy reload. */
772 if (ret == -EINVAL) {
773 pr_warn("audit rule for LSM \'%s\' is invalid\n",
774 df->lsm_str);
775 ret = 0;
776 }
777
778 return ret;
779 }
780
781 /* Duplicate an audit rule. This will be a deep copy with the exception
782 * of the watch - that pointer is carried over. The LSM specific fields
783 * will be updated in the copy. The point is to be able to replace the old
784 * rule with the new rule in the filterlist, then free the old rule.
785 * The rlist element is undefined; list manipulations are handled apart from
786 * the initial copy. */
787 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
788 {
789 u32 fcount = old->field_count;
790 struct audit_entry *entry;
791 struct audit_krule *new;
792 char *fk;
793 int i, err = 0;
794
795 entry = audit_init_entry(fcount);
796 if (unlikely(!entry))
797 return ERR_PTR(-ENOMEM);
798
799 new = &entry->rule;
800 new->flags = old->flags;
801 new->pflags = old->pflags;
802 new->listnr = old->listnr;
803 new->action = old->action;
804 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
805 new->mask[i] = old->mask[i];
806 new->prio = old->prio;
807 new->buflen = old->buflen;
808 new->inode_f = old->inode_f;
809 new->field_count = old->field_count;
810
811 /*
812 * note that we are OK with not refcounting here; audit_match_tree()
813 * never dereferences tree and we can't get false positives there
814 * since we'd have to have rule gone from the list *and* removed
815 * before the chunks found by lookup had been allocated, i.e. before
816 * the beginning of list scan.
817 */
818 new->tree = old->tree;
819 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
820
821 /* deep copy this information, updating the lsm_rule fields, because
822 * the originals will all be freed when the old rule is freed. */
823 for (i = 0; i < fcount; i++) {
824 switch (new->fields[i].type) {
825 case AUDIT_SUBJ_USER:
826 case AUDIT_SUBJ_ROLE:
827 case AUDIT_SUBJ_TYPE:
828 case AUDIT_SUBJ_SEN:
829 case AUDIT_SUBJ_CLR:
830 case AUDIT_OBJ_USER:
831 case AUDIT_OBJ_ROLE:
832 case AUDIT_OBJ_TYPE:
833 case AUDIT_OBJ_LEV_LOW:
834 case AUDIT_OBJ_LEV_HIGH:
835 err = audit_dupe_lsm_field(&new->fields[i],
836 &old->fields[i]);
837 break;
838 case AUDIT_FILTERKEY:
839 fk = kstrdup(old->filterkey, GFP_KERNEL);
840 if (unlikely(!fk))
841 err = -ENOMEM;
842 else
843 new->filterkey = fk;
844 break;
845 case AUDIT_EXE:
846 err = audit_dupe_exe(new, old);
847 break;
848 }
849 if (err) {
850 if (new->exe)
851 audit_remove_mark(new->exe);
852 audit_free_rule(entry);
853 return ERR_PTR(err);
854 }
855 }
856
857 if (old->watch) {
858 audit_get_watch(old->watch);
859 new->watch = old->watch;
860 }
861
862 return entry;
863 }
864
865 /* Find an existing audit rule.
866 * Caller must hold audit_filter_mutex to prevent stale rule data. */
867 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
868 struct list_head **p)
869 {
870 struct audit_entry *e, *found = NULL;
871 struct list_head *list;
872 int h;
873
874 if (entry->rule.inode_f) {
875 h = audit_hash_ino(entry->rule.inode_f->val);
876 *p = list = &audit_inode_hash[h];
877 } else if (entry->rule.watch) {
878 /* we don't know the inode number, so must walk entire hash */
879 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
880 list = &audit_inode_hash[h];
881 list_for_each_entry(e, list, list)
882 if (!audit_compare_rule(&entry->rule, &e->rule)) {
883 found = e;
884 goto out;
885 }
886 }
887 goto out;
888 } else {
889 *p = list = &audit_filter_list[entry->rule.listnr];
890 }
891
892 list_for_each_entry(e, list, list)
893 if (!audit_compare_rule(&entry->rule, &e->rule)) {
894 found = e;
895 goto out;
896 }
897
898 out:
899 return found;
900 }
901
902 static u64 prio_low = ~0ULL/2;
903 static u64 prio_high = ~0ULL/2 - 1;
904
905 /* Add rule to given filterlist if not a duplicate. */
906 static inline int audit_add_rule(struct audit_entry *entry)
907 {
908 struct audit_entry *e;
909 struct audit_watch *watch = entry->rule.watch;
910 struct audit_tree *tree = entry->rule.tree;
911 struct list_head *list;
912 int err = 0;
913 #ifdef CONFIG_AUDITSYSCALL
914 int dont_count = 0;
915
916 /* If any of these, don't count towards total */
917 switch(entry->rule.listnr) {
918 case AUDIT_FILTER_USER:
919 case AUDIT_FILTER_EXCLUDE:
920 case AUDIT_FILTER_FS:
921 dont_count = 1;
922 }
923 #endif
924
925 mutex_lock(&audit_filter_mutex);
926 e = audit_find_rule(entry, &list);
927 if (e) {
928 mutex_unlock(&audit_filter_mutex);
929 err = -EEXIST;
930 /* normally audit_add_tree_rule() will free it on failure */
931 if (tree)
932 audit_put_tree(tree);
933 return err;
934 }
935
936 if (watch) {
937 /* audit_filter_mutex is dropped and re-taken during this call */
938 err = audit_add_watch(&entry->rule, &list);
939 if (err) {
940 mutex_unlock(&audit_filter_mutex);
941 /*
942 * normally audit_add_tree_rule() will free it
943 * on failure
944 */
945 if (tree)
946 audit_put_tree(tree);
947 return err;
948 }
949 }
950 if (tree) {
951 err = audit_add_tree_rule(&entry->rule);
952 if (err) {
953 mutex_unlock(&audit_filter_mutex);
954 return err;
955 }
956 }
957
958 entry->rule.prio = ~0ULL;
959 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
960 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
961 entry->rule.prio = ++prio_high;
962 else
963 entry->rule.prio = --prio_low;
964 }
965
966 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
967 list_add(&entry->rule.list,
968 &audit_rules_list[entry->rule.listnr]);
969 list_add_rcu(&entry->list, list);
970 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
971 } else {
972 list_add_tail(&entry->rule.list,
973 &audit_rules_list[entry->rule.listnr]);
974 list_add_tail_rcu(&entry->list, list);
975 }
976 #ifdef CONFIG_AUDITSYSCALL
977 if (!dont_count)
978 audit_n_rules++;
979
980 if (!audit_match_signal(entry))
981 audit_signals++;
982 #endif
983 mutex_unlock(&audit_filter_mutex);
984
985 return err;
986 }
987
988 /* Remove an existing rule from filterlist. */
989 int audit_del_rule(struct audit_entry *entry)
990 {
991 struct audit_entry *e;
992 struct audit_tree *tree = entry->rule.tree;
993 struct list_head *list;
994 int ret = 0;
995 #ifdef CONFIG_AUDITSYSCALL
996 int dont_count = 0;
997
998 /* If any of these, don't count towards total */
999 switch(entry->rule.listnr) {
1000 case AUDIT_FILTER_USER:
1001 case AUDIT_FILTER_EXCLUDE:
1002 case AUDIT_FILTER_FS:
1003 dont_count = 1;
1004 }
1005 #endif
1006
1007 mutex_lock(&audit_filter_mutex);
1008 e = audit_find_rule(entry, &list);
1009 if (!e) {
1010 ret = -ENOENT;
1011 goto out;
1012 }
1013
1014 if (e->rule.watch)
1015 audit_remove_watch_rule(&e->rule);
1016
1017 if (e->rule.tree)
1018 audit_remove_tree_rule(&e->rule);
1019
1020 if (e->rule.exe)
1021 audit_remove_mark_rule(&e->rule);
1022
1023 #ifdef CONFIG_AUDITSYSCALL
1024 if (!dont_count)
1025 audit_n_rules--;
1026
1027 if (!audit_match_signal(entry))
1028 audit_signals--;
1029 #endif
1030
1031 list_del_rcu(&e->list);
1032 list_del(&e->rule.list);
1033 call_rcu(&e->rcu, audit_free_rule_rcu);
1034
1035 out:
1036 mutex_unlock(&audit_filter_mutex);
1037
1038 if (tree)
1039 audit_put_tree(tree); /* that's the temporary one */
1040
1041 return ret;
1042 }
1043
1044 /* List rules using struct audit_rule_data. */
1045 static void audit_list_rules(int seq, struct sk_buff_head *q)
1046 {
1047 struct sk_buff *skb;
1048 struct audit_krule *r;
1049 int i;
1050
1051 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1052 * iterator to sync with list writers. */
1053 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1054 list_for_each_entry(r, &audit_rules_list[i], list) {
1055 struct audit_rule_data *data;
1056
1057 data = audit_krule_to_data(r);
1058 if (unlikely(!data))
1059 break;
1060 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1061 data,
1062 sizeof(*data) + data->buflen);
1063 if (skb)
1064 skb_queue_tail(q, skb);
1065 kfree(data);
1066 }
1067 }
1068 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1069 if (skb)
1070 skb_queue_tail(q, skb);
1071 }
1072
1073 /* Log rule additions and removals */
1074 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1075 {
1076 struct audit_buffer *ab;
1077
1078 if (!audit_enabled)
1079 return;
1080
1081 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1082 if (!ab)
1083 return;
1084 audit_log_session_info(ab);
1085 audit_log_task_context(ab);
1086 audit_log_format(ab, " op=%s", action);
1087 audit_log_key(ab, rule->filterkey);
1088 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1089 audit_log_end(ab);
1090 }
1091
1092 /**
1093 * audit_rule_change - apply all rules to the specified message type
1094 * @type: audit message type
1095 * @seq: netlink audit message sequence (serial) number
1096 * @data: payload data
1097 * @datasz: size of payload data
1098 */
1099 int audit_rule_change(int type, int seq, void *data, size_t datasz)
1100 {
1101 int err = 0;
1102 struct audit_entry *entry;
1103
1104 switch (type) {
1105 case AUDIT_ADD_RULE:
1106 entry = audit_data_to_entry(data, datasz);
1107 if (IS_ERR(entry))
1108 return PTR_ERR(entry);
1109 err = audit_add_rule(entry);
1110 audit_log_rule_change("add_rule", &entry->rule, !err);
1111 break;
1112 case AUDIT_DEL_RULE:
1113 entry = audit_data_to_entry(data, datasz);
1114 if (IS_ERR(entry))
1115 return PTR_ERR(entry);
1116 err = audit_del_rule(entry);
1117 audit_log_rule_change("remove_rule", &entry->rule, !err);
1118 break;
1119 default:
1120 WARN_ON(1);
1121 return -EINVAL;
1122 }
1123
1124 if (err || type == AUDIT_DEL_RULE) {
1125 if (entry->rule.exe)
1126 audit_remove_mark(entry->rule.exe);
1127 audit_free_rule(entry);
1128 }
1129
1130 return err;
1131 }
1132
1133 /**
1134 * audit_list_rules_send - list the audit rules
1135 * @request_skb: skb of request we are replying to (used to target the reply)
1136 * @seq: netlink audit message sequence (serial) number
1137 */
1138 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1139 {
1140 u32 portid = NETLINK_CB(request_skb).portid;
1141 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1142 struct task_struct *tsk;
1143 struct audit_netlink_list *dest;
1144 int err = 0;
1145
1146 /* We can't just spew out the rules here because we might fill
1147 * the available socket buffer space and deadlock waiting for
1148 * auditctl to read from it... which isn't ever going to
1149 * happen if we're actually running in the context of auditctl
1150 * trying to _send_ the stuff */
1151
1152 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1153 if (!dest)
1154 return -ENOMEM;
1155 dest->net = get_net(net);
1156 dest->portid = portid;
1157 skb_queue_head_init(&dest->q);
1158
1159 mutex_lock(&audit_filter_mutex);
1160 audit_list_rules(seq, &dest->q);
1161 mutex_unlock(&audit_filter_mutex);
1162
1163 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1164 if (IS_ERR(tsk)) {
1165 skb_queue_purge(&dest->q);
1166 kfree(dest);
1167 err = PTR_ERR(tsk);
1168 }
1169
1170 return err;
1171 }
1172
1173 int audit_comparator(u32 left, u32 op, u32 right)
1174 {
1175 switch (op) {
1176 case Audit_equal:
1177 return (left == right);
1178 case Audit_not_equal:
1179 return (left != right);
1180 case Audit_lt:
1181 return (left < right);
1182 case Audit_le:
1183 return (left <= right);
1184 case Audit_gt:
1185 return (left > right);
1186 case Audit_ge:
1187 return (left >= right);
1188 case Audit_bitmask:
1189 return (left & right);
1190 case Audit_bittest:
1191 return ((left & right) == right);
1192 default:
1193 BUG();
1194 return 0;
1195 }
1196 }
1197
1198 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1199 {
1200 switch (op) {
1201 case Audit_equal:
1202 return uid_eq(left, right);
1203 case Audit_not_equal:
1204 return !uid_eq(left, right);
1205 case Audit_lt:
1206 return uid_lt(left, right);
1207 case Audit_le:
1208 return uid_lte(left, right);
1209 case Audit_gt:
1210 return uid_gt(left, right);
1211 case Audit_ge:
1212 return uid_gte(left, right);
1213 case Audit_bitmask:
1214 case Audit_bittest:
1215 default:
1216 BUG();
1217 return 0;
1218 }
1219 }
1220
1221 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1222 {
1223 switch (op) {
1224 case Audit_equal:
1225 return gid_eq(left, right);
1226 case Audit_not_equal:
1227 return !gid_eq(left, right);
1228 case Audit_lt:
1229 return gid_lt(left, right);
1230 case Audit_le:
1231 return gid_lte(left, right);
1232 case Audit_gt:
1233 return gid_gt(left, right);
1234 case Audit_ge:
1235 return gid_gte(left, right);
1236 case Audit_bitmask:
1237 case Audit_bittest:
1238 default:
1239 BUG();
1240 return 0;
1241 }
1242 }
1243
1244 /**
1245 * parent_len - find the length of the parent portion of a pathname
1246 * @path: pathname of which to determine length
1247 */
1248 int parent_len(const char *path)
1249 {
1250 int plen;
1251 const char *p;
1252
1253 plen = strlen(path);
1254
1255 if (plen == 0)
1256 return plen;
1257
1258 /* disregard trailing slashes */
1259 p = path + plen - 1;
1260 while ((*p == '/') && (p > path))
1261 p--;
1262
1263 /* walk backward until we find the next slash or hit beginning */
1264 while ((*p != '/') && (p > path))
1265 p--;
1266
1267 /* did we find a slash? Then increment to include it in path */
1268 if (*p == '/')
1269 p++;
1270
1271 return p - path;
1272 }
1273
1274 /**
1275 * audit_compare_dname_path - compare given dentry name with last component in
1276 * given path. Return of 0 indicates a match.
1277 * @dname: dentry name that we're comparing
1278 * @path: full pathname that we're comparing
1279 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1280 * here indicates that we must compute this value.
1281 */
1282 int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen)
1283 {
1284 int dlen, pathlen;
1285 const char *p;
1286
1287 dlen = dname->len;
1288 pathlen = strlen(path);
1289 if (pathlen < dlen)
1290 return 1;
1291
1292 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1293 if (pathlen - parentlen != dlen)
1294 return 1;
1295
1296 p = path + parentlen;
1297
1298 return strncmp(p, dname->name, dlen);
1299 }
1300
1301 int audit_filter(int msgtype, unsigned int listtype)
1302 {
1303 struct audit_entry *e;
1304 int ret = 1; /* Audit by default */
1305
1306 rcu_read_lock();
1307 list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1308 int i, result = 0;
1309
1310 for (i = 0; i < e->rule.field_count; i++) {
1311 struct audit_field *f = &e->rule.fields[i];
1312 pid_t pid;
1313 u32 sid;
1314
1315 switch (f->type) {
1316 case AUDIT_PID:
1317 pid = task_pid_nr(current);
1318 result = audit_comparator(pid, f->op, f->val);
1319 break;
1320 case AUDIT_UID:
1321 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1322 break;
1323 case AUDIT_GID:
1324 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1325 break;
1326 case AUDIT_LOGINUID:
1327 result = audit_uid_comparator(audit_get_loginuid(current),
1328 f->op, f->uid);
1329 break;
1330 case AUDIT_LOGINUID_SET:
1331 result = audit_comparator(audit_loginuid_set(current),
1332 f->op, f->val);
1333 break;
1334 case AUDIT_MSGTYPE:
1335 result = audit_comparator(msgtype, f->op, f->val);
1336 break;
1337 case AUDIT_SUBJ_USER:
1338 case AUDIT_SUBJ_ROLE:
1339 case AUDIT_SUBJ_TYPE:
1340 case AUDIT_SUBJ_SEN:
1341 case AUDIT_SUBJ_CLR:
1342 if (f->lsm_rule) {
1343 security_task_getsecid(current, &sid);
1344 result = security_audit_rule_match(sid,
1345 f->type, f->op, f->lsm_rule);
1346 }
1347 break;
1348 case AUDIT_EXE:
1349 result = audit_exe_compare(current, e->rule.exe);
1350 if (f->op == Audit_not_equal)
1351 result = !result;
1352 break;
1353 default:
1354 goto unlock_and_return;
1355 }
1356 if (result < 0) /* error */
1357 goto unlock_and_return;
1358 if (!result)
1359 break;
1360 }
1361 if (result > 0) {
1362 if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE)
1363 ret = 0;
1364 break;
1365 }
1366 }
1367 unlock_and_return:
1368 rcu_read_unlock();
1369 return ret;
1370 }
1371
1372 static int update_lsm_rule(struct audit_krule *r)
1373 {
1374 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1375 struct audit_entry *nentry;
1376 int err = 0;
1377
1378 if (!security_audit_rule_known(r))
1379 return 0;
1380
1381 nentry = audit_dupe_rule(r);
1382 if (entry->rule.exe)
1383 audit_remove_mark(entry->rule.exe);
1384 if (IS_ERR(nentry)) {
1385 /* save the first error encountered for the
1386 * return value */
1387 err = PTR_ERR(nentry);
1388 audit_panic("error updating LSM filters");
1389 if (r->watch)
1390 list_del(&r->rlist);
1391 list_del_rcu(&entry->list);
1392 list_del(&r->list);
1393 } else {
1394 if (r->watch || r->tree)
1395 list_replace_init(&r->rlist, &nentry->rule.rlist);
1396 list_replace_rcu(&entry->list, &nentry->list);
1397 list_replace(&r->list, &nentry->rule.list);
1398 }
1399 call_rcu(&entry->rcu, audit_free_rule_rcu);
1400
1401 return err;
1402 }
1403
1404 /* This function will re-initialize the lsm_rule field of all applicable rules.
1405 * It will traverse the filter lists serarching for rules that contain LSM
1406 * specific filter fields. When such a rule is found, it is copied, the
1407 * LSM field is re-initialized, and the old rule is replaced with the
1408 * updated rule. */
1409 int audit_update_lsm_rules(void)
1410 {
1411 struct audit_krule *r, *n;
1412 int i, err = 0;
1413
1414 /* audit_filter_mutex synchronizes the writers */
1415 mutex_lock(&audit_filter_mutex);
1416
1417 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1418 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1419 int res = update_lsm_rule(r);
1420 if (!err)
1421 err = res;
1422 }
1423 }
1424 mutex_unlock(&audit_filter_mutex);
1425
1426 return err;
1427 }
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